Work continues on widening Highway 99 to six lanes through Manteca.

HIME ROMERO/The Bulletin

Manteca residents can expect possible low water pressure during peak use periods for two weeks starting Thursday.

Work on the new Lathrop Road interchange on Highway 99 is requiring the relocation of the pipeline that supplies surface drinking water to Manteca from the water treatment plant operated by South San Joaquin Irrigation District 16 miles away near the base of Woodward Reservoir.

The pipeline also supplies water to Lathrop and Tracy. Those two cities will also have to rely on their well water for the two-week period.

During the shutdown from May 30 through June 13 the city will rely on groundwater wells to supply water to its customers. The city expects to meet all needs but anticipates low water pressure during the morning peak demand from 5 to 8 a.m. and the evening peak demand from 6 to 9 p.m.

It also means surface water won’t be available to mix with well water at some wells within the city to reduce arsenic levels. The city will continue to operate these wells to meet customer needs during the pipeline shutdown after receiving approval from the California Department of Health to do so. The state emphasized there will be no immediate threat to public health as a result.

The new bridge’s foundation need to be built over where the existing pipeline is now located. It is expected to take two weeks to relocate the pipeline.

The new Lathrop Road interchange will have a four-lane overcrossing, sidewalks, and bike lanes. The bridge will have an upgraded design along with Tidewater-style street lights. The interchange will also be landscaped. As part of the interchange project, the flyover onramp from North Main Street will be removed.

The interchange requires:

• realigning the West Frontage Road through Delta College’s property in the northwest corner of the interchange and align it with Crestwood Avenue. Delta College is proposing developing 350,000 square feet of retail on the land.

• extending North Main as four lanes from Northgate Drive to tie into an intersection with the southbound on and off ramps at Lathrop Road. The road is designed to allow traffic to travel at 35 mph.

• relocating the East Frontage Road further east and extend it south of Lathrop Road behind developed parcels before curving back to the existing Frontage Road to provide access to Southland Road.

The new interchange will provide a direct route for trucks accessing business and industrial parks that exist and are proposed between Lathrop and Manteca along the Airport Way corridor. It will also provide a direct truck route between Interstate 5 and Highway 99 in addition to the Highway 120 Bypass and French Camp Road.

The interchange is part of the $250 million widening of 13.1 miles of Highway 99 between Arch Road and the 120 Bypass from four to six lanes.